1. Field of the Invention
The present invention relates to a channel search method and system for a vertical handoff in a wireless network environment. More particularly, the present invention relates to a channel search method and system for a vertical handoff and a wireless local area network (WLAN) service subscription in a wireless network environment.
2. Description of Related Art
Recently, there has been dramatic development in wireless communication networks. Various communication networks such as cellular-based mobile communication networks, wireless broadband Internet (WiBro) networks, wireless local area networks (WLANs), and wireless personal area networks (WPANs) provide users with a variety of communication services.
Along with advancements in communication networks, there have been developments in mobile communication terminals. Terminals such as multi-mode mobile communication terminals are now being introduced that can receive services from various heterogeneous communication networks. Multi-mode mobile communication terminals include a plurality of wireless interfaces, and may connect to various wireless communication networks.
A vertical handoff operation from a single communication network to another communication network is required so that multi-mode mobile communication terminals provide reliable service among scattered heterogeneous communication networks. For such vertical handoff, mobile communication terminals search for a communicable channel with WLAN nodes when the mobile communication terminals enter coverage areas of the WLAN nodes, and select the communicable channel, and thereby may set an association and authorization with the WLAN nodes. To locate the communicable channel, the mobile communication terminals perform a successive channel search from a first channel to an eleventh channel. Also, the mobile communication terminals locate the communicable channel and use the communicable channel for setting the association.
However, a time delay in the vertical handoff may be caused in heterogeneous wireless environments due to the successive channel search.
For example, when the communicable channel is the eleventh channel, a great amount of time may be spent in locating the channel, and the mobile communication terminals may unnecessarily waste energy.
Accordingly, there is a need for a channel search method and system for a vertical handoff in a wireless network environment to overcome such disadvantages of the conventional art, and provide more efficient vertical handoff.